Field of the Invention
The present invention relates to methods of controlling the growth of microorganisms in animals and animal feed. In particular, the present invention relates to a method of controlling the growth of microorganisms in animals with an antimicrobial composition, the treatment of animal feed with an antimicrobial additive and antimicrobial compositions.
Background of the Invention
In modern animal farming, various methods have been explored to improve animal health and growth performance. These include better husbandry management, better nutrition and the utilization of feed additives. The most common feed additives used are antibiotics, probiotics, enzymes and organic acids (Bernardeau, M., J. P. Vernoux and M. Gueguen, (2002), “Safety and efficacy of probiotic lactobacilli in promoting growth in post-weaning Swiss mice”, Int J. Food Microbiol. 77:19-27).
However, extensive use of antibiotics in feed may cause animals to become resistant to antibiotics used to treat bacterial infections in animals as well as humans (Mikkelsen L. L., Jensen B. B., (2000), “Effects of fermented liquid feed on the activity and composition of the microbiodata in the gut of pigs”, Pig News Inform. 21:59N-66N). This led to a ban of marketing and use of antibiotics as growth promoters in feed by the European Commission on Jan. 1 2006. Consumer pressure in other countries such as the US is pushing animal production to phase out use of antibiotics as growth promoters. Removal of antimicrobial growth promoters from animal feed has sparked the interest for identifying new non-therapeutic alternatives with microbial growth modulating effects in order to sustain a healthy animal intestinal microflora (Huyghebart, Ducatelle and Immerseel, (2011), Veterinary J., 187:182-188).
One source of pathogenic bacteria in animal production is contaminated animal feed. Animal feed is normally heat treated to kill harmful bacteria and pathogens. However, incomplete heat treatment can result in 10-15% of Salmonella remaining, and/or incorrect storage of animal feed can further result in feed contaminated with bacteria (see F. T. Jones, 2011, Poult. Sci. 83:384-391 for a general review). When the animal eats the contaminated feed, the animal can become infected with the bacteria which eventually can end up with the consumer buying contaminated food in the supermarket. The use of organic acids, often blended with formaldehyde, has been used to control the amount of Salmonella in feed after the pelleting process. However, formaldehyde can give regulatory issues and organic acids alone often need several days at inclusion rates of 1% to destroy existing bacteria. These high levels of acids may be costly, be corrosive to milling and feeding equipment and have adverse effects with feed palatability and the availability of vitamins to animals.
Description of the Related Art
U.S. Pat. No. 4,320,116 describes the use of an antibacterial system capable of being activated in the gastrointestinal tract of an animal comprising a lactoperoxidase, a thiocyanate and a water soluble peroxide donor such as an alkali percarbonate or alkali perodide. U.S. Pat. No. 5,389,369 describes the use of a haloperoxidase and an antimicrobial activity enhancing agent, such as an alpha-amino acid, for killing or inhibiting the growth of yeast of sporular microorganisms in the treatment of human or animal subjects and in vitro disinfection applications.
WO00/21381 describes the use of two antimicrobial enzymes, such as a lysozyme and an oxidase, together with an enhancer, such as a polyunsaturated fatty acid, to improve growth and feed conversion ratio (FCR) in for example poultry, pigs and cows.
U.S. Pat. No. 5,747,078 describes a method for the long term preservation of food products, such as cheese, comprising an oxidoreductase that generates hydrogen peroxide from a substrate and a lactoperoxidase. U.S. Pat. No. 5,310,541 describes an animal chew which contains an oxidoreductase and corresponding substrate (such as glucose oxidase and glucose) that generates an antimicrobial agent on being chewed to help prevent e.g. cavies and periodontal diseases in animals.
US2002/0119136 describes a method of killing or inhibiting a microorganisms e.g. in laundry, on hard surfaces, on human skin or in oral care, comprising contacting said microorganism with a composition containing a peroxidase, hydrogen peroxide or a source of hydrogen peroxides such as glucose oxidase/glucose, and a enhancing agent such as a phenothiazine derivative or a syringate derivative. U.S. Pat. No. 4,726,948 describes an anti-bacterial composition capable of being activated in the GI tract of mammals comprising Lactoferrin, a lactoperoxidase and an activating system such as glucose/glucose oxidase.
US2011/229598 discloses an antimicrobial milk product comprising a lactoperoxidase, a glucose oxidase, glucose and an oxidizable agent for feeding to calves. EP1068871 describes an antimicrobial feed complement for calves or toothpaste for pets comprising a lactoperoxidase, a glucose oxidase, glucose, thiocyanate, Lactoferrin, lysozyme, immunoglobulin's and growth factors. EP2510944 discloses an antimicrobial feed complement for cows comprising a lactoperoxidase or chloroperoxidase, a glucose oxidase, iodide, and either glucose or a beta-galactosidase.